| 摘要 |
<p>A passive microphone (110), which is wireless and battery-less, contains a resonant sensor circuit (112) and a reactive sensor (114) sensitive to vibration may be remotely coupled to a receiver circuit (130). The sensor (114) is a passive condenser microphone wherein vibration of the diaphragm alters the condenser capacitance and the resonant frequency of the resonant sensor circuit (112). The passive microphone is directly or indirectly attached to the person and is coupled to a remotely disposed reader (120) carried by the person and then is transmitted to a remote receiver (130). The passive microphone sensor (114) exposed to vibrations alters the resonance frequency of a sensor circuit (112) containing the sensor (114). Wireless coupling of the sensor circuit (112) to a reader circuit (122) changes the impedance of the reader circuit (122) that is detectable upon sequentially exciting the reader circuit (122) over a range of frequencies that includes the resonance frequency.</p> |
